Autoantigens are tissue components of an organism to which that organism directs an immune response. The condition which results from such a self-directed immune response is known as autoimmunity (or "autoallergy"). Proteins on or on sperm are known to be potent autoantigens, and autoimmunity to such proteins is believed a significant cause of infertility.
R. Shabanowitz and M. O'Rand, Ann. NY Acad. Sci. 541, 621-632 (1988), at FIG. 7, describes various human proteins which have affinity for human zona pellucida.
M. O'Rand and E. Widgren, U.S. Pat. No. 5,175,148, discloses a sperm antigen which corresponds to an autoantigenic epitope of Rabbit Sperm Membrane Autoantigen (RSA). RSA is now known to be a family of four low molecular weigh glycoproteins (RSA-1,2,3,4: 14K, 16K, 17K, 18K) which function as high affinity zona binding proteins. The cloning of rabbit RSA 3 (also called "sp17") is described in R. Richardson and M. O'Rand, Mol. Biol. Cell. 3, 15a (1992).